title: Greenfield filter fixation in large venae cavae.
abstract: OBJECTIVE
  It is generally thought that the Greenfield filter should not be placed in inferior venae cavae (IVCs) that are larger than 28 mm in diameter because of its base diameter. However, the newer versions have larger base diameters. The purpose of this study was to evaluate fixation of the three currently available Greenfield filters in large IVCs.
  
  
  METHODS
  Filter fixation was tested in an ex vivo perfusion system with a 34-mm-diameter equine IVC. Greenfield filters with base diameters of 30 mm (original 24-F version [24-F GF]), 38 mm (percutaneous titanium [TGF]), and 32 mm (percutaneous stainless steel [SGF]) were deployed. Increasing force was then applied in a cephalic direction and the resultant movement was measured.
  
  
  RESULTS
  In a 34-mm-diameter IVC, the TGF and SGF demonstrated significantly less movement than did the 24-F GF (P < .001). None of the TGFs or SGFs moved above the renal veins with a 480-g pull. Three of the seven 24-F GFs moved above the renal veins at 30 g. No significant difference in fixation was demonstrated between the TGF and the SGF (P = .6).
  
  
  CONCLUSIONS
  In a 34-mm-diameter IVC, fixation of the TGF and SGF was significantly better than the 24-F GF. The TGF and SGF may not be subject to the same 28-mm-diameter IVC size limitation as the 24-F GF.
authors.affiliation: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Savin
authors.forename: R D
authors.initials: RD
authors.lastname: Shlansky-Goldberg
mesh_terms: D000818:Animals; D004867:Equipment Design; D005548:Foreign-Body Migration; D006736:Horses; D013193:Stainless Steel; D014025:Titanium; D014656:Vascular Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior / Q000601:surgery*
chemical_list: D013193:Stainless Steel; D014025:Titanium